Bind OP25 control API and terminal to loopback by default

Both :8001 (FastAPI control API) and :8081 (OP25's HTTP terminal) listened on
0.0.0.0 with no authentication, on a container that is privileged with /dev
mounted and network_mode: host. Nodes get deployed to third-party sites, so
that exposed start/stop/retune to anyone on the host's LAN.

All three containers share the host network namespace, so edge-node still
reaches both over 127.0.0.1 unchanged. OP25_DEBUG_EXPOSE=true restores the
old 0.0.0.0 binding and logs a loud warning; it is off by default.

Confirmed against boatbod/op25 gr310 that the terminal's http:<host>:<port>
string is honoured as a real bind address (http_server.py splits it and hands
the host to create_server), so no flag was invented.

Also reorder models.py so IcecastConfig precedes ConfigGenerator, which
annotates a field with it. That only worked because python:slim-trixie is
currently Python 3.14, where PEP 649 defers annotation evaluation; on 3.13 or
earlier the same file is a hard NameError at import.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

op25-container/Dockerfile

@@ -50,5 +50,8 @@ RUN sed -i 's/\r$//' /usr/local/bin/docker-entrypoint.sh && \
 # 2. Update ENTRYPOINT to use the wrapper script
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]
 
-# 3. Use CMD to pass the uvicorn command as arguments to the ENTRYPOINT script
-CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8001", "--reload"]
+# 3. Use CMD to pass the launch command as arguments to the ENTRYPOINT script.
+# main.py starts uvicorn itself (see `if __name__ == "__main__"`) so the bind
+# address can be driven by OP25_DEBUG_EXPOSE at runtime instead of being baked
+# into this image at build time.
+CMD ["python", "main.py"]